Renesas HD6417641 用户手册

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Section 20   USB Function Module 
Rev. 4.00  Sep. 14, 2005  Page 752 of 982 
REJ09B0023-0400 
 
Bit Bit 
Name 
Initial 
Value R/W 
Description 
EP3TR 
R/W 
EP3 Transfer Request 
This bit is set if there is no valid transmit data in the 
FIFO buffer when an IN token for endpoint 3 is 
received from the host. A NACK handshake is 
returned to the host until data is written to the FIFO 
buffer and packet transmission is enabled. 
EP3TS 
R/W 
EP3 Transmit Complete 
This bit is set when data is transmitted to the host 
from endpoint 3 and an ACK handshake is returned. 
VBUS 
R/W 
UBS Disconnection Detection 
This bit is set to 1 when a function is connected to or 
disconnected from the USB bus. Use the VBUSCNT 
pin of this module to detect connection/disconnection. 
 
20.3.3 
USB Interrupt Flag Register 2 (USBIFR2) 
Together with USB interrupt flag registers 0 (USBIFR0) and 1 (USBIFR1), USBIFR2 indicates 
interrupt status information required by the application. When an interrupt occurs, the 
corresponding bit is set to 1 and an interrupt request is sent to the CPU according to the 
combination with USB interrupt enable register 2 (USBIER2). Clearing is performed by writing 0 
to the bit to be cleared, and 1 to the other bits. However, CFGV is a status bit, and cannot be 
cleared. USBIFR2 is initialized to H'20 by a power-on reset. 
Bit Bit 
Name 
Initial 
Value R/W Description 
 
 
 
 
Reserved 
The write value should always be 0. 
3 AWAKE 
0 R/W 
Awake 
Signal Detection 
This bit is set to 1 when the resume or bus reset signal 
is detected on the USB bus in the suspend state with 
USBCTRL/SUSPEND = 1. 
SUSPS 
R/W 
USB Suspend Signal Detection 
This bit is set to 1 when the USB suspend signal is 
detected with USBCTRL/SUSPEND = 1.